A Promising Step Against Virus That Hobbles Many

January 31, 2010|By Thomas H. Maugh II Tribune Newspapers

LOS ANGELES - — U.S. researchers have developed a prototype vaccine that protects monkeys and mice against the emerging chikungunya virus, a major step toward the production of a vaccine for humans. Human trials could begin later this year.

Chikungunya is a mosquito-borne virus that first appeared on Reunion Island off the eastern coast of Africa in 2005 and has spread to more than 18 countries, infecting millions.

It is characterized by rash, a high fever and its most distinctive characteristic: a severe arthritis that can persist for years. There are currently no effective treatments and no preventive measures for the virus, and health authorities are concerned that it could cause a pandemic.

Public health authorities fear that the virus will spread more widely because it has adapted to the Asian tiger mosquito, which survives in temperate climates and is widespread. Increases in global travel and climate change may also encourage its spread, according to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

To attack the problem, institute virologist Gary Nabel and his colleagues adapted technology that is already used in vaccines against hepatitis B and human papillomavirus.

They produced a particle that contains the outer protein shell of the virus - which allows it to be recognized by the immune system - but not the viral genetic information, preventing it from replicating.

The team reported Thursday in the online version of the journal Nature Medicine that immunization of rhesus macaque monkeys with the particles provided full immunity when the animals were subsequently exposed to the live virus.

Antibodies against the virus were then isolated from the monkeys and injected into immunodeficient mice.

The antibodies protected the mice from a subsequent exposure to a normally lethal dose of the virus.

In addition to human trials of the new vaccine, Nabel and his team plan to study whether a similar approach could be used to protect against the related western and eastern equine encephalitis viruses found in the United States and the o'nyong-nyong virus found in Africa.

tmaugh@tribune.com

INFORMATIONAL BOX:

Chik*un*gun*ya

Chikungunya means "he who walks bent over" in the Kimakonde language of Mozambique, an allusion to the gait of the people who succumb to it, according to an article in the journal PLoS Neglected Tropical Diseases.